Managing Food Materials

No grease in the sewer. This fact sheet is provided to encourage businesses such as food service providers, processors, distributors, and merchandisers to eliminate waste and recover/recycle food materials. Food waste can produce several environmental impacts. For example, food materials discharged to a wastewater treatment plant will contribute to increased levels of BOD (biological oxygen demand), COD (chemical oxygen demand), TSS (total suspended solids), and O/G (oil and grease). Examples of these food materials include preparation wastes, uneaten portions, grease, batter waste, dairy products, beverages containing sugar, and dressings. Also, food materials discarded into the solid waste stream contribute to odor and methane generation at disposal facilities and to increased BOD and COD levels in landfill leachate.


Food materials are excellent candidates for reduction, recovery, and reuse. Reducing materials at their source, coupled with recovery, reuse, and recycling prevents pollution and reduces, and in some cases eliminates, treatment and disposal costs. A successful waste reduction program
can result in cost savings and possible generation of revenues. These activities also contribute to a positive public image for the company, benefits to the community, and protection of the environment.

Reduction at the Start: Ordering and Inventory Controls

Perhaps the most effective method for reducing waste is to prevent it in the first place. Proper control of raw goods,final products, and the waste streams associated with food preparation is an important source reduction technique. Improved ordering and inventory control significantly affect
the three major sources of waste resulting from improper inventory control: excess, out-of-date, and obsolete raw goods. Below are options for reduction at the start.

  • Order bulk supplies.
  • Terminate useless packaging from the vendor.
  • Refuse samples that will become waste.
  • Work with suppliers to return shipping materials and packaging.
  • Purchase reusable items.
  • Purchase durable items such as air hand dryers that are designed to reduce waste.
  • Purchase only the amount of raw goods needed for set period of time. This practice will help eliminate out-of-date and excess goods and products.
  • Develop a review and approval procedure for all raw goods and products purchased. The primary purchaser can regulate the quantity of materials purchased by other personnel to reduce excess and out-of-date inventory.
  • Clearly label all materials. Labels can indicate contents, storage and handling, and expiration dates.

Donations, Sales, and Composting of Food Material

Food preparation businesses seeking to reduce food waste should look for opportunities to work closely with potential users such as food donor programs. Food businesses may also work with facilities such as grease renderers, animal food manufacturers,
local farmers, or composters who can collect food materials and use them in their operations. Composting is also an option for managing solid food waste. Table 1 lists North Carolina renderers, animal food manufacturers, and composting facilities. Tables 2 and 3 list North Carolina and national food bank/food donor programs.

Segregate Food Wastes for Beneficial Uses

To increase their recyclable potential, food materials should be clean and free of trash such as paper, glass, and plastic. Also, depending upon the requirements of recyclers, solid food wastes should be separated from liquid food wastes to enhance their recyclability.

  • Excess edible food should be kept separate from
    waste food and routed to a local food bank or food
    donor program. North Carolina’s model “Good
    Samaritan Law” was enacted in 1989 and revised
    in 1991. This law protects any good faith donor
    from civil or criminal liability unless injury is caused
    by gross negligence, recklessness, or intentional misconduct
    of the donor. The local health department
    can provide handling and storage procedures applicable
    to your area. Currently, more than four
    million pounds of food materials are donated each
    year to North Carolina food rescue programs alone.
     
  • Solid food waste should be segregated from waste
    oils and greases. Hog, cattle, and poultry producers
    are interested in collecting food waste to use as
    animal feed. Dairy and bread waste may be fed to
    hogs without further handling, but other food waste
    or mixed food waste must be cooked before being
    fed to hogs. Farmers who use other or mixed food
    materials must be licensed garbage feeders. Zylphia
    Smith of the U.S. Department of Agriculture, Animal
    Plant Health Inspection Services (APHIS) at
    (919) 856-4170 can provide information about state
    regulations and a list of licensed garbage feeders.
    Local cooperative extension agents also may assist
    with locating markets for waste food.
     
  • Waste oils and grease
     
    Free grease is that used for or generated by cooking
    and has not been mixed with water. It is
    generated from pots, pans, grills, and deep fat
    fryers and comes from butter, lard, vegetable
    fats and oils, meats, nuts, and cereals. Free
    grease should be kept out of the drains and
    handled separately. Rendering facilities may
    purchase free grease and meat wastes and provide
    storage and collection. The market price
    depends upon factors such as volume, quality,
    and hauling distances. The rendering services
    will process free grease by sampling it for pesticides
    and other chemicals and filtering and
    volatizing impurities before reselling it, where
    prices may range from one to three cents per
    pound. If the volume of the wastes generated
    from one restaurant or cafeteria is too small
    for the rendering facility, businesses should explore
    the feasibility of setting up a cooperative
    collection among similar businesses.
     
    Trap grease is that collected in a grease trap.
    Because fats coat, congeal, and accumulate on
    pipes and pumps and sometimes obstruct sewer
    lines, some food service establishments may be
    required by their local government to maintain
    grease traps. Specific information about trap
    maintenance is presented below. Some rendering
    services and local septage haulers will service
    or pump out these traps for a fee, and some
    services may reduce the pumping fee if the restaurant
    is a free grease customer.

Dry Cleanup To Keep Wastes Out of the Drain

Food preparation facilities should develop dry cleanup procedures to the greatest possible extent. Some municipalities will charge (surcharge) for any discharge of BOD, COD, TSS, and O/G above a certain level. For a restaurant that uses 3,000 gallons of water per day, serves seven days a week, and has an average BOD of 1,250 milligrams per liter (mg/ L), an annual surcharge could be as much as $1,173.1 Dry cleanup procedures will reduce the amount of food waste that enters the drains and, thus, help reduce the possible surcharges.

The “first pass” in equipment and utensil cleaning should be made with scrapers, squeegees, or
absorbents to prevent the bulk of food materials from going down the drain. Studies have shown
that for a fast food restaurant, 93 percent of the oil and grease discharged to the wastewater treatment plant is generated from ware washing. For a full service restaurant, 75 percent of the oil and grease discharged to the wastewater treatment plant is generated from the pot sink. Waste collected on this “first pass” could be set aside for rendering or, possibly, composting.

Spills. Dry cleanup can be applied also to spills in the kitchen. Spills of dry ingredients should be swept up or vacuumed to prevent them from being washed down the drain.

Garbage Disposals. Businesses that use garbage disposals to dispose of food waste are simply transferring disposal from a landfill to a wastewater treatment plant. Disposal of food waste via the sewer system is more costly than landfill disposal and acts as a disincentive to reduce generation of food waste or to separate food for donations, rendering, animal feed, or composting.

Maintaining Grease Traps

Food preparation facilities that discharge to a municipal sewer should contact the local wastewater treatment plant (WWTP) for any requirements concerning the need for interceptors and grease trap management. The most important management procedure for grease traps is that a company
representative be present during any cleaning, pumping, or skimming performed by a contractor. This safeguard permits management to respond appropriately to any questions about the services performed.

  • Pump out schedules should be properly established and strictly followed to prevent overflows, downstream blockage, excessive oil and grease, and BOD loading to wastewater. It is important that these pump outs are complete, i.e., the grease caps removed, the sides scraped or hosed down, and the trap refilled with water. The contractor should indicate whether the trap is refilled with clean water or water from the trap.
  • A food preparation facility should never “hot flush” (continuously run hot water) the grease trap as the heated, liquefied grease will be flushed down the sewer. While hot flushing may divert the need for pumping, the facility is liable for any costs associated with clogs caused by the flushing.
  • Skimming services are available to skim grease traps on a regular basis. These facilities will reprocess the grease collected and notify owners when complete grease trap pump outs are necessary.
  • Bioaugmentation, the addition of selected microorganisms (primarily bacteria) to the trap for improved operation, should be evaluated for each case. The bioaugmentation process is basically a passive treatment system to facilitate grease digestion and control buildup of the grease cap. The effectiveness of bioaugmentation is determined by a variety of factors including retention time in the trap, temperature of the wastewater, strength of the wastewater, and contact surface area. Some information indicates that for completely effective bioaugmentation, a retention time of one to five days is needed; however, a typical grease trap is designed for only one day of hydraulic retention. Since these parameters vary with location, an evaluation of each case should be made. The local WWTP should be contacted before any additives are used.
  • Alternative grease trap designs. Some grease trap systems are designed to periodically heat the trap to de-solidify grease so that it can be automatically skimmed and collected. The high-quality grease collected from these systems may have high reuse potential.
    These grease traps, which may also be smaller than standard traps, can be located under
    a specific device above ground (i.e., the pot sink).

Composting Food Wastes

Compost Facilities. Businesses interested in diverting wastes to composting could open their own compost facility or investigate the possibility of using local government or private compost facilities already in operation. North Carolina has a compost demonstration program for individuals interested in composting. For regulatory information or a list of pilot or permanent composting facilities for organic materials, contact Ted Lyon of the Solid Waste Section (SWS) of the N.C. Division of Solid Waste Management at (919) 733 0692, ext. 253. Both the SWS and the Division of Pollution Prevention and Environmental Assistance can provide information and technical assistance to businesses interested in establishing and managing a composting program.

Facility Waste Reduction Program

Management Commitment. The most critical step to successful waste reduction is commitment by the owner(s)/managers of a facility to a waste management plan. A detailed waste reduction program should be developed that outlines policies and procedures for dealing with waste and assigns individual responsibilities for all waste related activities.

Employees will be aware of the degree of commitment by management and will rise or fall to the level that is expected or allowed. It is, therefore, important to have realistic goals that can be achieved, recognized, and rewarded.

Employee training is a significant component of a waste reduction program, and all employees from managers to the clean-up crew should be included. The training sessions, which should be repeated on a regular basis, should teach waste awareness, the impact of various food wastes on the wastewater stream, proper waste handling methods, and the importance of keeping non-food garbage out of food waste containers.

Contact the Division of Pollution Prevention and Environmental Assistance at (919) 715-6500 for assistance with setting up training programs.

An Employee Suggestion/Awards Program should be established to maintain employee motivation. Employees can be rewarded for proper waste handling practices. Current incentive programs (“employee of the month”) can also incorporate employee waste handling practices as evaluation criteria. An employee awareness program should be highly visible, and managers and supervisors must strongly support these programs.

Also, employees should be solicited for ideas/suggestions for conducting efficient dry cleanups, segregating food wastes, or recycling other solid waste products. Employees also may have ideas about methods to generate less food waste or more effectively manage inventory. The most effective waste reduction programs make use of a team concept in which employees at all levels make contributions.